George (The Death of Rhythm and Blues) calls this wide-ranging history of hip-hop a ""book of memory"" and compares his relationship with the music to a love affair. A portrait not just of the music but of the whole culture coalescing around beats and rhymes, from graffiti to break dancing and basketball, George's narrative sometimes jumps from topic to topic like the fragmentary soundscapes of his subject. Nonetheless, he does follow a loose, anecdotal trajectory from the ""post-soul"" era of the early 1980s through the Old School to the New School, through gangsta rap to the latest innovators. Often, detours seem to be taken solely because George couldn't bear to drop material, and the writing can seem hasty. One may disagree with certain assessments (he says of trendy vocalist and hip-hop impresario Puff Daddy, ""Never in the history of postwar black pop has a single man done so much so well""), but quibbling aside, the author's knowledge and passion run deep. George conveys a continuing excitement and personal investment rather than pretending critical distance, still rethinking his own past positions. Most refreshingly, while an advocate, he is blunt and perceptive in areas where traditional hip-hop advocates can be blindly protective. The book is at its best when George is more commentator than chronicler; one wishes more space had been devoted to exploration of many provocative issues raised in passing: Is democracy good for art? Why no great women rappers? One such thought George offers is that art can be suffocated when ""loved too well by the people [it was] intended to make uncomfortable""; the best audience for these memories may turn out to be those outsiders rather than hip-hop purists. (Oct.)